A new wave of environmentally minded science-ranging from aviation materials to papermaking-is breaking into industries, promising to reduce damage to natural forests.
Two professors at U of T’s forestry department, Drs. Malcolm Campbell and Mohini Sain, are caught up in this movement, which aims to use trees more efficiently.
Campbell’s aim is “to develop a mechanistic understanding of how whole plants function.” By identifying genes that dictate a plant’s uptake of carbon, say, it is possible to enhance trees in economically desirable ways. In other words, we can fiddle with their genes to enhace their core competences.
Consider the pulp and paper industry. Students and businesses use enormous amounts of fine white paper. But such paper requires the expenditure of large amounts of money and energy to remove natural lignin from wood cellulose.
While cellulose constitutes the bulk of white paper, lignin is entirely undesirable. A sort of molecular glue in trees, lignin is removed, only to form polychlorinated phenols, or PCPs, which are released into the environment. Remaining lignin is then bleached to produce white paper.
“It’s economically and environmentally costly,” said Campbell. “It would be really desirable if we could find a way of not only identifying trees that can fix more carbon, but when they put that carbon away, it gets disproportionately channelled into cellulose as opposed to lignin.”
One way of making such trees is by entering promising tree species into breeding programs. By selecting for a favourable trait, trees can be bred to make more cellulose than lignin.
Campbell’s model assigns functions to forests: some will be farmed for human use, some will sequester greenhouse carbon and clean our air, and others will provide an alternate energy source. Most importantly, natural forests will remain undisturbed. The Canadian Forest Service has adopted this solution to go toward meeting emissions goals set by the Kyoto Accord.
“I’ll buy that any day of the week over someone going over the Carmanah Valley with a chainsaw,” said Campbell.
But there’s more than one way to approach the problem of our deteriorating forests and meeting rising demands for wood. Today, 60 per cent of the world’s wood supply is used for heating. Mohini Sain, another tree-lover in the forestry department, looks to add value to each tree cut down, so we may save those still standing.
“Our focus in biomaterials is based on lignocellulosic materials, trees, barks,” Sain explained. Cellulose, the natural fibre that constitutes much of the useful parts of wood, is refined down to a micro and nanofibre. This process can also be applied to lumber wastes. The high strength properties of micro and nanofibres allow them to incorporate into plastics, without disparities in performance.
The result is a composite material for automotive parts, aviation materials, and food-packaging films that work just as well, but can be programmed to biodegrade after use.
Instead of eating up the earth’s invaluable fossil fuel store by making plastic, researchers have developed “BioBest” plastic that comes from and returns to the earth. “If we can add value to our natural resources, then we’re not going to take so much from [them],” said Sain.
Environmentally, bioplastics cause fewer greenhouse gas emissions, preserve fossil fuels, and add value to trees. The current problem involves scaling the industrial process up to reap economies of scale.
“We can do it scientifically, but how can we do it economically?” asked Sain.
But already, companies around the world are making use of biodegradable composite materials. Chemical makers Cargill-Dow and Ingeo derive bioplastic from corn poly-lactic acid (PLA). Out of these, they make consumer products as diverse as plastic cutlery and duvets and mattresses.
In Europe and Japan, Mercedes-Benz and Toyota are making car doors and parts out of plant materials, like sugar cane, corn PLA, and flax. Toyota boasts of easy-to-dismantle car parts made out of “Eco-Plastic” in its new Japanese model, the Raum.
Home to ten per cent of the world’s forests, Canada’s lumber industry generates billions for our economy and directly supports the livelihoods of thousands. But it is also an industry that dumps toxins in our air and water, and threatens the sustainability of forests.
We now have some tools and models to tackle these problems. And Sain, for one, is optimistic: “I think in the next 50 years we’ll be living in a different society.”
